[ad_1]
February 16, 2023 – A highly contagious strain of bird flu – known as H5N1 – is sweeping the world, devastating backyard flocks and commercial farms. While this virus primarily infects birds, increasing reports of mammals infected with the virus have some experts worried. The main concern, they say, is that as H5N1 continues to spread and multiply in different species, there are more opportunities for the virus to potentially acquire mutations that could help it infect humans more easily. .
“Just by simple numbers game, the more likely it is to infect humans or [other] mammals, the more likely you are for this rare event to occur,” says Richard Webby, PhD, director of the World Health Organization Collaborating Center for Studies of Influenza Ecology in Animals and Birds at St. Jude Children’s Hospital in Memphis.
As of May 2022, the United States Department of Agriculture has detected 121 mammals infected with the H5N1 virus, including red foxes, skunks, bears and even seals. In October 2022, an epidemic in a mink farm in Spain led to the culling of more than 51,000 animalsand earlier this month, Peru confirmed 585 sea lions have died from the virus in coastal nature reserves. Although H5N1 infections have been detected in mammals for the past 25 years, “we are definitely seeing an increase in reported cases over the past 12 months,” Webby says.
The World Health Organization said the risk to humans remains low, “but we cannot assume this will remain the case, and we must be prepared for any change in the status quo,” the director said. General of the WHO, Tedros Adhanom Ghebreyesus, PhD, at a briefing this month.
Human infections remain rare
H5N1 infections in humans are rare. They primarily occur when a person is exposed directly and unprotected to H5N1-infected birds or surfaces contaminated with the virus. Since 1997, there have been approximately 870 human cases reported to WHO, about half of whom die from the infection. Even if someone is infected with the virus, it is even rarer for the infection to spread to another human being.
“The H5N1 viruses currently circulating in wild birds and causing outbreaks in poultry are well suited to spread among birds,” said Tim Uyeki, MD, chief medical officer of the Office of the Director of Influenza Division at CDC. , in a press release. online questions and answers. “However, these H5N1 avian influenza viruses do not have the ability to easily bind to receptors in the upper respiratory tract of humans, or to transmit between people.”
Even with the record number of infected wild birds and poultry, human infections have become rarer in recent years. Since the beginning of this century, it was not uncommon to have at least 30 to 40 human H5N1 recorded per year. Since 2021, there have been fewer than 10 reported infections worldwide, according to the CDC.
More spread in mammals
H5N1 infections in wild mammals are not unheard of, although they are also rare events. Most of these cases likely occur when an animal eats an infected bird and is exposed to the virus. As in humans, these infections have been sporadic. But one report last month An outbreak at a mink farm in Spain has experts worried as researchers have suggested the virus may have spread through one mink by infecting others. Mink are related to ferrets, which scientists use as an animal model to study flu transmission.
“If we see something that is transmitted in mink, it’s not a stretch to think, ‘Maybe this is something that could also be transmitted in ferrets,'” Webby says. “We would certainly use transmission in ferrets as a wake-up call for human risk.”
But so far, there’s been no evidence that the virus has acquired the ability to more easily infect humans, says William Schaffner, MD, professor of infectious diseases at Vanderbilt University Medical Center in Nashville.
“In fact, one of the reassuring things is that at this mink farm in Spain, the people who work on the farm – and have had very close contact with these minks – have all been tested, and they have come out negative. “, he says. The minks were also very tightly confined in cages – which may have contributed to the spread of the virus, he notes.
The most recent report of infections in sea lions has led some people to speculate online about the possible spread of the virus among animals, but these marine mammals may also have been exposed to H5N1-infected birds.
What’s clear is that the virus is widespread and showing up in more and more animals, says Jennifer Nuzzo, DrPH, who directs the Pandemic Center at Brown University School of Public Health in Providence, RI. Why this happens is less obvious.
“Does that mean that [H5N1] acquired some aptitude for mammals? What does this mean for the potential to infect humans? We just don’t know,” she said.
Will bird flu become the next pandemic?
Unfortunately, it is not possible to predict which type of virus will cause the next pandemic. But the WHO’s Global Influenza Surveillance and Response System is already hard at work monitoring flu strains around the world, Schaffner says.
“It’s like a radar system, which tries to detect the enemy” as soon as possible, he says. The network not only tracks infections in humans, but also in birds and other animals.
While bird flu has begun to pose a real threat to the public, the United States already has a stockpile of bird flu vaccines.
“If we need them, they can be updated to the latest strain and immediately start manufacturing,” Schaffner says.
Although experts agree that the risk to the public of contracting H5N1 is low, people should avoid contact with sick or dead wild birds, poultry and wild animals. Do not eat uncooked or undercooked poultry, eggs and other poultry products. It is safe to eat cooked poultry, poultry products and eggs. Additional protective measures can be found on the CDC website.
|
Sources 2/ https://www.webmd.com/a-to-z-guides/news/20230216/bird-flu-infecting-more-mammals-what-to-know The mention sources can contact us to remove/changing this article |
[ad_2]